Fix BUG-026: forward mouse wheel to full-screen agents#812
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The native Hera view's mouse-wheel scroll routes through HeraPage.MouseHandler -> regionAt -> the pane under the cursor. If a wheel event misses the pane rects it falls through to FocusRail, where the rail has no MouseHandler, so Box.MouseHandler does not consume it and tview never redraws (Application redraws a mouse event only when consumed) -- scroll-up silently does nothing. The existing TestPanes_MouseRoutingByRegion scrolls over the agent region but never asserts the scroll landed. Add two assertions that close that gap: - TestPanes_MouseScrollRoutesToWorkerPane: wheel over the agent region scrolls the selected live worker's TerminalPane (consumed + scrollOffset increases). - TestPanes_MouseScrollRoutesToCoordPane: with a coordinator selected (Details mode), wheel over the coord region scrolls the coordinator pane. Investigation note: the BUG-026 report (cannot mouse-scroll-up in new/active Hera sessions) could not be reproduced on this base -- routing and scrollback both behave correctly for live worker and coordinator panes. These tests pin that correct behavior as a regression guard while a precise repro is gathered. Test-only; no behavioral change. 🤖 Generated with [Claude Code](https://claude.com/claude-code) Co-Authored-By: Claude <noreply@anthropic.com>
…ty scrollback Agents like Claude Code / Codex run as full-screen TUIs: they take the alternate screen (ESC[?1049h) and redraw in place via cursor-home (ESC[H) instead of emitting scrolling output, so the terminal pane's own scrollback stays near-empty. The native Hera coord/agent panes (and the shared Tasks-tab agent view) scroll that scrollback on the mouse wheel, so wheel-up was a silent no-op whenever the agent rendered in place -- maxScroll clamps to 0 with no history to reveal. Confirmed by feeding two real session logs through the replay emulator: a coordinator that emitted scrolling output yielded ~2791 scrollback lines (scrollable); a worker that redrew in place yielded 0. Both were on the alternate screen, so alt-screen presence is not the discriminator -- committed scrollback depth is. NOT a routing/click-to-focus bug: the wheel reaches the pane (scroll-down visibly redrew); there was simply nothing in scrollback. Fix (matches how a real terminal hands the wheel to the foreground full-screen app, and the existing plugin-view forwarder #681): when the live agent is on the alternate screen, TerminalPane.MouseHandler forwards wheel events to the agent as SGR mouse frames (ESC[<64|65;Cx;Cy M) via sess.WriteInput so the agent scrolls its own view. Main-screen agents and finished/replay sessions keep the pane's own terminal scrollback unchanged. Mouse-only -- no keybinding/help changes. Specs: openspec/changes/fix-bug-026 (terminal-rendering delta). 🤖 Generated with [Claude Code](https://claude.com/claude-code) Co-Authored-By: Claude <noreply@anthropic.com>
…ding to full-screen agents) Base spec updated atomically with the merged fix per CLAUDE.md. The lone incomplete task (6.1 live dogfood) is the pending runtime verification on Aaron's relaunch.
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Summary
In the Hera panes and the Tasks-tab agent view, the mouse wheel did nothing on a freshly-started agent session — you couldn't scroll up. Older sessions scrolled fine.
Root cause (not an argus regression): Claude Code (and Codex) recently default to a fullscreen mode — the alternate screen (
ESC[?1049h) with in-place cursor-home redraws. A full-screen TUI has no terminal scrollback by definition (sbLen=0,maxScroll=0), so the pane's wheel-scroll had nothing to reveal. This is faithful terminal behavior — you can't wheel-scroll a full-screen TUI in any terminal. Old sessions scrolled only because they had accumulated main-buffer scrollback (a bug-bash-2 coordinator measuredsbLen≈2791vs a fresh worker'ssbLen=0, both on the alternate screen). The "recent regression" was the upstream Claude Code default change, not an argus commit.Fix
TerminalPane.MouseHandlernow forwards the wheel to a live, alternate-screen agent as SGR mouse frames (ESC[<64;Cx;Cy Mwheel-up,65wheel-down) over the session input, so the agent scrolls its own view — exactly how a real terminal hands the wheel to a foreground full-screen app (mirrors the plugin-view forwarder, #681). Agents enable SGR mouse reporting (1000h/1002h/1003h/1006h), so the frames are understood.TerminalPane, so this fixes both the Hera coord/agent panes and the Tasks-tab agent view.Verification
forward_wheel_test.go(forwards-when-alt-screen, scrolls-scrollback-when-not) + Hera routing regression tests.make pre-pr: build / vet / fmt-check / lint-pr (0 issues) / test-cover-gate (89.5% ≥ 88 floor) all green. Thevulngate flags two Go stdlib CVEs (net/textproto,crypto/x509; fixed in go1.26.4) — toolchain-only, not this change, and advisory (continue-on-error) in CI.Spec
OpenSpec
terminal-renderingcapability gains a "Mouse wheel forwarded to full-screen agents" requirement (changefix-bug-026, archived into base specs in this PR).🤖 Generated with Claude Code